shiningfury

I hadn't thought to look at the Archives tab; all of the original HRDLCs were checked. I unchecked the three of them and restarted MO - the optimized Dawnguard and Dragonborn folders are now overwriting their unoptimized originals (Hearthfire_Optimized still shows as redundant). Many thanks for all the information and patient help. This is a great community.

After following the guide at https://wiki.step-project.com/Guide:DDSopt/Skyrim my results match those of junglejudas; namely, Mod Organizer indicates that the optimized folders for Dawnguard, Hearthfires, and Dragonborn are redundant. Here is a screenshot of the relevant part of MO: https://i.imgur.com/lSnHzsa.jpg And here is a screenshot of the Conflicts tab of my Dawnguard_Optimized with one of the examples you provided: https://i.imgur.com/lTy7eaf.jpg I just finished the optimization and have only tested for a few minutes in the game around Riverwood and don't see any problems, but I thought it might be useful to provide another example of possibly redundant files being manipulated during the process outlined in the excellent guide on the wiki.